"But, er, if those numbers are to be believed, then Microsoft runs about 8.5 servers per rack, which seems disheartening in this day and age of bladey goodness."
Depends which are you look at, assuming that both sets of data are sorted alphabetically which they appear to be if you match overall server count with Kw consumed in the two screen grabs.
They appear to show that for example Columbia has 37,230 servers in 2,550 making 14.6 severs per rack on average, however Dublin has 1,209 servers in 318 racks making 3.8 servers per rack.
Interestingly if we take these figures and combine them with the utility power consumed we see that Columbia uses roughly 300W/server and Dublin is running at 950W/server???.
i have to say that 950W for a server seems a little high so maybe i have fudged something along the way, although if you check out Amsterdam they come out at a thoroughly respectable 288W/server.
Can a server consume nearly 1Kw? do these consumption figures include operating costs, i.e lighting, air con etc.